Process of casting pottery



VMay 5, 1925.

roh 24. 1924 wif A. E. STACEY, JR

PROCESS OF CASTING POTTERY Filed Ma www juf

, ,y Patented May 5, 1925,

ELERED EsTAcEY, JRL, or ESSEX EELLs, NEW JERSEY, AssIGNoR'ro caRRiER EN- erNEERINe CORPORATION, or NEWARK, NEW JERSEY.

' PROCESS or oas'riNerorTERY.

. Application filed March 24, 19245j Serial No. 701,410.

T all 'whom t 77mg/ concern:

yBe, it known that l, ALFRED E. STACEY,

' Jr-a citizen of the United States, residing at Essex Fells, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Processes of CastingPottery, of which the following is a specification.

'- ln casting' pottery, such for instance as porcelain tanks and other articles by the l methods commonly employed at the present time the sli 7 or fluid mixture of cla-vs and a P other` ingredients used for making the casts or pottery is poured into molds of the re quired'shapes. When molding hollow pot- I tery of this character, as is well known, a

core is used in the mold leaving a space bevtween the mold and core conforming in shape andv dimensions to the walls of the article. The slip-ordinarily used is a fluid mixture composed of a blend of suitable clays having` the required characteristics, flint, spar, water and electrolytes;` sodium carbonate andl sodium silicate. Usually about 30 per cent of water is used in the mixture and the slip is cold, or at its natural temperature when poured into' the y molds. lln the average commercial pottery v works'` the slip is mixed in large tanks-and 3o then pumped to the d1fl'erent casting floors through pipe lines, flexiblehose being connected at the necessary points with' the pipe lines and equipped with faucets, so that the molder can move around among his molds and lill them from the faucets. rllhe molds and cores are made of suitable material, such as plaster of Paris which is adapted to' ab Q sorb moisture from the slip inthe molds, and after a mold is poured it is'allowed to I 4o' stand until sufficient water has been absorbed from the slip by the mold and core to make the cast stiff enough to stand without the core. 'The core is then removed which should be done'befole enough water 45 is absorbed to cause. the cast to'shrink enough to cling tothe core and spoil the piece bv cracking at the corners. 'llhe piece is thennleft inthe mold until it has shrunk percentage of imperfect castings especially in the case of 'articles having relatively thick 'Walls or portons. that these can be o /viated and the product .greatly improved by heating; the slip as hereinafter more fully explained so that it will have a temperature sufficiently higher than its natural temperature when being poured into the molds.n l

According to my invention, therefore, the slip is heatedl and 4is poured while warm. l have l found that by thus using the heated slip, the cores can be removed from the molds after standing a very muchl shorter time and the castings are tougher and stiffer.

The, castingsT also showl a freedom from stratification, piping and balling in the l corners which are common imperfections in this typeof work when cold slip isused. Another benefit which I found is in freeing the slip from air bubbles. The heat expands the air stirred into the slip yduring the compounding thereof and also makes it more fluid so that the bubbles can escape when the slip is carefully stirred. Corner cracks are also eliminated to a large extent. articles cast from cold slip these occur chiefly'when there is a thicker section and it is necessary to leave the core in the mold a sufficient time to'allow the clay to set, but

there is so much contraction of the casting that the corners around the core are broken apart. It is possible with the heated slip to make consistently good castings in shapes which practicall preclude them from/being cast from cold s ip. v

Preferably theslip is heated in a closed vessel so as to prevent the loss of moisture, although this might be compensated for by the addition of Water after heating, or preferably by starting with a slip having a higher water content. Jacketed kettles heated by steam or hot water afford a convenient means for heating the` slip. l pre'- fer to heat the slip-after the Imining ofits ingredients and just prior to pouring it into the' molds and to stir the slip vinthe heating vessel, after the heating period, to remove the air: bubbles. llf the bubbles remain in break through the surfaces of the casts during the firing and Spoil the ware.

lin plants' which are equipped to pipe the slip to the points where the molds are lo-y l have discovered l Vso cated, the-cold slip bispreferably pumped from the mixing tank or tanks to a heatingl trouble of pipe linesv becoming clogged. Each heatingrvessel should be of suicient capacity to take,- care ofa days or a half days casting so that there will bel no slip to be returned to the main mixing tanks.

The temperature to which the slip should be heated may vary more or less, depending upon the composition of the different slips used and the proportion of sodium silicate and sodium carbonate therein. The best results have been obtained with temperatures between about 1309 F. and about 141:0o F., although temperatures ranging from approximately 105 F. to 170o F. have shown substantial improvements in results, and there appears to be. advantage in 'any increase in-the temperature of the slip above natural temperatures.

In the accompanying drawings:

Fig. 1 is a perspective View of' a mold assembled ready for molding a porcelain tank by my hereindescribed metho Fig. 2 is a sectionalfview through the mold showing the pottery material therein.

10 and 11 represent respectively the body and the core of the mold which, as usual are' preferably made of plaster of Paris and in the form required for fthe piece of' pottery ware to be cast. The coreis removably secured in place in thevmold body by the usual clamping boards 12 and 1.3 and bolts 14 and the slip'is poured into the mold through the usual tunnels 15 at the` top of the mold. The manner of usingl the mold in casting the pottery from heated slip in accordance with my invention has been already explained.

This prevents objecw tionable cooling of the slip and avoids the I 1 claim as my invention: p 1. rlhe hereindescribed process ofcasting pottery which consists in using a fluid slip which is heated toa temperature higher than natural temperatures, and casting the heaty ed slip into the desired shape.

2. The hereindescribedprocess of casting pottery which consists in using a Vfluid slip which is heated to a temperature higher than natural temperatures, and pouring 'the heated slip into a mold which is adapted to absorb moisture from the slip.

3. The hereindescribed process of casting pottery which consists inl mixing the necessary ingredients to make a fluid slip, heating the slip and pouring the heated slip into a mold which is adapted to absorb moisture from the slip.

4. The hereindescribed process of casting pottery which consists in mixing the necessary ingredients to make a fluid slip, ,heating the slip after mixing the same and before casting the slip, and then' casting the heated slip into the desired shape. n

5. The hereindescribed process of casting pottery Which consists in using a fluid slip which is heated to a temperature higher than naturall temperatures, stirring the heated slip to remove airbubbles, andl casting the heated slip into the desired shape. 6. Thehereindescribed process of casting 'pottery which consists in using a fluid slip which is heated to a temperature between approximately 120 F.and approximately 150o F., and casting the heated slip into the desired shape. l

7. The hereindescribed process of casting pottery which consists in mixing the necessary ingredients fto make a Huid slip, heating the-slip to a-temperature between about 130o F. and about 140 F., and casting the heated slip into the desired shape.` i

ALFRED n. sTACEY, JR. 

